A passion for plant life

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Growth and development of the banana plant3. A. The origin of the inflorescence and the development of the flowers: B. The structure and development of the fruit

In this paper, which is presented in two parts, the growth and development of the banana plant have been examined from the standpoint of the origin of the inflorescence and the development of the flowers (Part A) and the structure and development of the fruit (Part B). First the main centres of growth in these structures are located and the manner of their development is presented. Thereafter, attention is focused upon the salient events which determine the alternative courses of development with a view to designating the chemical and physiological stimuli that may be required

Shortening the juvenile phase for flowering in Kalanchoe pinnata Pers

Plants of Kalanchoe pinnata flower normally at the end of 2 years. Flowering in the juvenile phase (3- and 9-month-old plants) has been induced by application of gibberellin (GA) either to the shoot tip and the youngest pair of leaves, or to the third leaf. Three-month-old plants required more exogenous GA (50 μg/plant) than 9-month-old plants (5 μg/plant). The simultaneous application of the growth retardant (2-chloroethyl)trimethylammonium chloride=CCC via the roots did not interfere with GA-induced flowering but overcame the inhibitory effects produced by a high concentration of GA (150 μg/plant) when applied alone

Retardation of inflorescence development in Calendula officinalis by a morphactin and its application

The morphactin - chlorflurenol at 1, 5, 25, 125 and 625 μg/plant either caused total damage of the shoot apices or allowed a few inflorescences to develop with few or no flowers. The inflorescences arising in the lateral branches showed suppressed bracts and modified flowers. With time the treated plants recovered and showed a significant increase in the growth of laterals and the number of inflorescences. Thus morphactin can be used for prolonging the growth period and for obtaining more wholesome plants

In-vitro induction of aerial leaves and of precocious flowering in submerged shoots of Limnophila indica by abscisic acid

Nodal explants of submerged shoots of Limnophila indica (L.) Druce were cultured in Nitsch's liquid medium containing abscisic acid (ABA, 10-9-10-6 M). At 10-7 and 10-6 M, ABA induced typical aerial leaves (entire, ovate, opposite-decussately arranged) even under submerged conditions and completely suppressed the development of water leaves (pinnately dissected and whorled). Flowers that invariably arise from aerial shoots were induced precociously by ABA even on submerged nodes

Morphogenic potentialities of flower buds of Kalanchoe pinnata Pers. grown in vitro

Excised flower buds of Kalanchoe pinnata Pers. representing two early stages of development (designated sets I and II), were cultured on modified White's medium (WB). They failed to attain full development on WB or on WB containing any of the following supplements: indole-3yl-acetic acid (IAA), 2,4-dichlorophenoxyacetic acid (2,4-D), naphthaleneacetic acid (NAA), kinetin, or coconut milk (CM). A slight stimulation of the growth of corolla was caused by kinetin (10 ppm). IAA (I ppm) and NAA (I ppm) induced rooting from the cut end of the pedicel and from the proliferated torus tissue situated between the sepals and petals. 2,4-D (I ppm) either singly or in concert with CM (10 per cent) stimulated the formation of shoot buds and root growth. Addition of kinetin (I and 10 ppm) to WB favoured shoot formation, but suppressed rooting. Flower buds of set II developed shoot buds more readily than those of set I. Thus, the primordia floral organs present in the immature buds lose their ability for normal morphogenesis under culture conditions. Buds destined to form flowers can be made to revert to vegetative growth

Induction of male flowers on female plants of Cannabis sativa by gibberellins and its inhibition by abscisic acid

Gibberellins (GA3, GA4+7, GA7 and GA9) induce male flowers on female plants of Cannabis sativa. This is, depending on concentration, partially or fully inhibited by abscisic acid (ABA). The ABA effect can in turn be partially overcome by increasing the concentration of GA3

Contributions of Panchanan Maheshwari's school to angiosperm embryology through an integrative approach

P. Maheshwari who served as Professor and Head of the Department of Botany, University of Delhi from 1950 to 1966 built a flourishing school of embryology which became internationally recognized. His colleagues and students have contributed significantly to all areas of embryology through integrative approaches. In memory of his birth centenary year, we have prepared this article that summarizes the work done by his students and traces the phenomenal advances made in some areas in the post-Maheshwari era

Fruit development and structure in some Indian bamboos

Fruit structure and development of seven species belonging to five genera of Indian bamboos are described. The fruit in four species is a caryopsis typical of the family Poaceae. The ovule is bitegmic; the outer surface of the cells of nucellar epidermis becomes cutinized and forms the seed coat. Three species bear a fleshy fruit with a unitegmic ovule. In a mature fruit the endosperm is either completely absorbed by the embryo or is present only in small quantity. The developing embryo comes in direct contact with the fruit wall due to the disintegration of the nucellus and integument. The embryo is covered by a thick brown mat from the disorganized cells of the inner layers of the fruit wall

Systematic significance of mature embryo of bamboos

The mature embryo of seven species belonging to five genera of Indian bamboos is described. In all these the basic pattern of embryo organisation is same: the scutellar and coleoptilar bundles are not separated by an internode, the epiblast is absent, the lower portion of the scutellum and the coleorhiza are separated by a cleft and the margins of embryonic leaves overlap. The features unique to fleshy fruited bamboos are: presence of a massive scutellum, the juxtaposition of plumule and radicle and the occurrence of a bud in the axil of the coleoptile. The fleshy fruit bearing bamboos should be classified into one group, the tribeMelocanneae. Evidence is provided to recognise additional groups in the subfamily Bambusoideae